Why was Swan of Jeremiah Johnson killed by the Crow Indians?

Swan, a character in the film "Jeremiah Johnson," is killed by the Crow Indians due to a combination of cultural misunderstandings and the tensions between settlers and Native Americans. After Swan, who is of mixed heritage, inadvertently offends the Crow by entering their territory and trying to live among them, they view him as a threat. His death serves as a catalyst for Jeremiah Johnson's quest for revenge and highlights the tragic consequences of conflict between different cultures during that period.